From 2ee5c90f0239d162b40aea5d24c26dcb44b82032 Mon Sep 17 00:00:00 2001
From: Vladimir Agafonkin <agafonkin@gmail.com>
Date: Thu, 2 Jan 2014 15:42:14 +0200
Subject: [PATCH] add CRS.Earth, move Harvesine distance there

---
 build/deps.js               |  1 +
 src/geo/LatLng.js           | 17 +----------------
 src/geo/crs/CRS.EPSG3395.js |  7 ++-----
 src/geo/crs/CRS.EPSG3857.js |  7 ++-----
 src/geo/crs/CRS.EPSG4326.js |  7 ++-----
 src/geo/crs/CRS.Earth.js    | 22 ++++++++++++++++++++++
 6 files changed, 30 insertions(+), 31 deletions(-)
 create mode 100644 src/geo/crs/CRS.Earth.js

diff --git a/build/deps.js b/build/deps.js
index 502e7679..a1bb9fdb 100644
--- a/build/deps.js
+++ b/build/deps.js
@@ -15,6 +15,7 @@ var deps = {
 		      'geo/projection/Projection.SphericalMercator.js',
 		      'geo/crs/CRS.js',
 		      'geo/crs/CRS.Simple.js',
+		      'geo/crs/CRS.Earth.js',
 		      'geo/crs/CRS.EPSG3857.js',
 		      'geo/crs/CRS.EPSG4326.js',
 		      'map/Map.js',
diff --git a/src/geo/LatLng.js b/src/geo/LatLng.js
index 37791f99..9f89ed62 100644
--- a/src/geo/LatLng.js
+++ b/src/geo/LatLng.js
@@ -34,23 +34,8 @@ L.LatLng.prototype = {
 		        L.Util.formatNum(this.lng, precision) + ')';
 	},
 
-	// Haversine distance formula, see http://en.wikipedia.org/wiki/Haversine_formula
-	// TODO move to projection code, LatLng shouldn't know about Earth
 	distanceTo: function (other) {
-		other = L.latLng(other);
-
-		var R = 6378137, // earth radius in meters
-		    rad = Math.PI / 180,
-		    dLat = (other.lat - this.lat) * rad,
-		    dLon = (other.lng - this.lng) * rad,
-		    lat1 = this.lat * rad,
-		    lat2 = other.lat * rad,
-		    sin1 = Math.sin(dLat / 2),
-		    sin2 = Math.sin(dLon / 2);
-
-		var a = sin1 * sin1 + sin2 * sin2 * Math.cos(lat1) * Math.cos(lat2);
-
-		return R * 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));
+		return L.CRS.Earth.distance(this, L.latLng(other));
 	}
 };
 
diff --git a/src/geo/crs/CRS.EPSG3395.js b/src/geo/crs/CRS.EPSG3395.js
index e51755c5..4318d708 100644
--- a/src/geo/crs/CRS.EPSG3395.js
+++ b/src/geo/crs/CRS.EPSG3395.js
@@ -2,9 +2,8 @@
  * L.CRS.EPSG3857 (World Mercator) CRS implementation.
  */
 
-L.CRS.EPSG3395 = L.extend({}, L.CRS, {
+L.CRS.EPSG3395 = L.extend({}, L.CRS.Earth, {
 	code: 'EPSG:3395',
-
 	projection: L.Projection.Mercator,
 
 	transformation: (function () {
@@ -13,7 +12,5 @@ L.CRS.EPSG3395 = L.extend({}, L.CRS, {
 		    scale = 0.5 / (Math.PI * r);
 
 		return new L.Transformation(scale, 0.5, -scale, 0.5);
-	}()),
-
-	wrapLng: [-180, 180]
+	}())
 });
diff --git a/src/geo/crs/CRS.EPSG3857.js b/src/geo/crs/CRS.EPSG3857.js
index 1d77f4a5..1601b7d7 100644
--- a/src/geo/crs/CRS.EPSG3857.js
+++ b/src/geo/crs/CRS.EPSG3857.js
@@ -2,17 +2,14 @@
  * L.CRS.EPSG3857 (Spherical Mercator) is the most common CRS for web mapping and is used by Leaflet by default.
  */
 
-L.CRS.EPSG3857 = L.extend({}, L.CRS, {
+L.CRS.EPSG3857 = L.extend({}, L.CRS.Earth, {
 	code: 'EPSG:3857',
-
 	projection: L.Projection.SphericalMercator,
 
 	transformation: (function () {
 		var scale = 0.5 / (Math.PI * L.Projection.SphericalMercator.R);
 		return new L.Transformation(scale, 0.5, -scale, 0.5);
-	}()),
-
-	wrapLng: [-180, 180]
+	}())
 });
 
 L.CRS.EPSG900913 = L.extend({}, L.CRS.EPSG3857, {
diff --git a/src/geo/crs/CRS.EPSG4326.js b/src/geo/crs/CRS.EPSG4326.js
index f5eaf1a5..0420679f 100644
--- a/src/geo/crs/CRS.EPSG4326.js
+++ b/src/geo/crs/CRS.EPSG4326.js
@@ -2,11 +2,8 @@
  * L.CRS.EPSG4326 is a CRS popular among advanced GIS specialists.
  */
 
-L.CRS.EPSG4326 = L.extend({}, L.CRS, {
+L.CRS.EPSG4326 = L.extend({}, L.CRS.Earth, {
 	code: 'EPSG:4326',
-
 	projection: L.Projection.LonLat,
-	transformation: new L.Transformation(1 / 180, 1, -1 / 180, 0.5),
-
-	wrapLng: [-180, 180]
+	transformation: new L.Transformation(1 / 180, 1, -1 / 180, 0.5)
 });
diff --git a/src/geo/crs/CRS.Earth.js b/src/geo/crs/CRS.Earth.js
new file mode 100644
index 00000000..6cf86d8d
--- /dev/null
+++ b/src/geo/crs/CRS.Earth.js
@@ -0,0 +1,22 @@
+/*
+ * L.CRS.Earth is the base class for all CRS representing Earth.
+ */
+
+L.CRS.Earth = L.extend({}, L.CRS, {
+	wrapLng: [-180, 180],
+
+	R: 6378137,
+
+	// distane between two geographic points using Harvesine formula
+	distance: function (latlng1, latlng2) {
+		var rad = Math.PI / 180,
+		    lat1 = latlng1.lat * rad,
+		    lat2 = latlng2.lat * rad,
+		    sin1 = Math.sin((lat2 - lat1) / 2),
+		    sin2 = Math.sin((latlng2.lng - latlng1.lng) * rad / 2);
+
+		var a = sin1 * sin1 + sin2 * sin2 * Math.cos(lat1) * Math.cos(lat2);
+
+		return this.R * 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));
+	}
+});